Deacon Phillippe, 8, isn't going to be the baby of the family for much longer. With famous mom Reese Witherspoon pregnant with her third child, the celeb kid and older sister Ava, 12, "will love having a baby brother or sister," a source tells the current issue of Us Weekly of the Oscar winner's kids with her ex-husband, Ryan Phillippe.

Also psyched for baby? Witherspoon's husband of one year, Jim Toth, although it took him some time to warm up to the idea of first-time fatherhood, the source explains.

"Before Jim met Reese, he wasn't sure about having kids," the source tells Us of CAA agent Toth, 41. "Being around her kids has really shown him what it's all about." Indeed, Toth is "super-close with the kids," another insider adds, and now religiously attends Ava's school swim meets and Deacon's basketball games.

(Their papa, Phillippe, 37, however, is definitely not out of the picture. "He wants to be around just as often now that Ava and Deacon have a family unit with Jim," a third source explains of the actor. "They mean a great deal to him.")

As for Witherspoon, who is about 13 weeks along? "She wants to have this child and take time off," an insider says. And her cravings? Taco Bell! The Oscar winner was spotted indulging at the Mexican fast-food chain March 15.